flucky/pkg/sensor/dht22.go

package sensor

import (
	"context"
	"fmt"
	"sync"
	"time"

	"github.com/go-flucky/flucky/pkg/types"
	"github.com/go-flucky/go-dht"
	uuid "github.com/satori/go.uuid"
)

// DHT22 is a sensor to measure humidity and temperature.
type DHT22 struct {
	*types.Sensor
}

// GetSensorModel returns the sensor model
func (s *DHT22) GetSensorModel() types.SensorModel {
	return s.Sensor.SensorModel
}

// Read measured values
func (s *DHT22) Read() ([]types.MeasuredValue, error) {

	err := dht.HostInit()
	if err != nil {
		return nil, fmt.Errorf("HostInit error: %v", err)
	}

	gpio, err := types.GPIOToString(*s.GPIONumber)
	if err != nil {
		return nil, err
	}

	dht, err := dht.NewDHT(gpio, dht.Celsius, "")
	if err != nil {
		return nil, fmt.Errorf("NewDHT error: %v", err)
	}

	humidityValue, temperatureValue, err := dht.Read()
	if err != nil {
		return nil, fmt.Errorf("Read error: %v", err)
	}

	measuredValues := []types.MeasuredValue{
		&types.Humidity{
			HumidityID:       uuid.NewV4().String(),
			HumidityValue:    humidityValue,
			HumidityFromDate: time.Now(),
			HumidityTillDate: time.Now(),
			SensorID:         s.SensorID,
		},
		&types.Temperature{
			TemperatureID:       uuid.NewV4().String(),
			TemperatureValue:    temperatureValue,
			TemperatureFromDate: time.Now(),
			TemperatureTillDate: time.Now(),
			SensorID:            s.SensorID,
		},
	}

	return measuredValues, nil
}

// ReadChannel reads the measured values from the sensor and writes them to a
// channel.
func (s *DHT22) ReadChannel(measuredValuesChannel chan<- []types.MeasuredValue, errorChannel chan<- error, wg *sync.WaitGroup) {
	if wg != nil {
		defer wg.Done()
	}

	measuredValues, err := s.Read()
	if err != nil {
		errorChannel <- err
		return
	}

	measuredValuesChannel <- measuredValues

}

// ReadContinously reads the measured values continously from the sensor and
// writes them to a channel.
func (s *DHT22) ReadContinously(ctx context.Context, measuredValuesChannel chan<- []types.MeasuredValue, errorChannel chan<- error) {
	for {
		select {
		case <-ctx.Done():
			errorChannel <- fmt.Errorf("%v: Context closed: %v", s.SensorName, ctx.Err())
			return
		default:
			s.ReadChannel(measuredValuesChannel, errorChannel, nil)
		}
	}
}